2 * linux/kernel/irq/handle.c
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
7 * This file contains the core interrupt handling code.
9 * Detailed information is available in Documentation/DocBook/genericirq
13 #include <linux/irq.h>
14 #include <linux/module.h>
15 #include <linux/random.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel_stat.h>
18 #include <linux/rculist.h>
19 #include <linux/hash.h>
20 #include <linux/bootmem.h>
22 #include "internals.h"
25 * lockdep: we want to handle all irq_desc locks as a single lock-class:
27 struct lock_class_key irq_desc_lock_class
;
30 * handle_bad_irq - handle spurious and unhandled irqs
31 * @irq: the interrupt number
32 * @desc: description of the interrupt
34 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
36 void handle_bad_irq(unsigned int irq
, struct irq_desc
*desc
)
38 print_irq_desc(irq
, desc
);
39 kstat_incr_irqs_this_cpu(irq
, desc
);
43 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
44 static void __init
init_irq_default_affinity(void)
46 alloc_bootmem_cpumask_var(&irq_default_affinity
);
47 cpumask_setall(irq_default_affinity
);
50 static void __init
init_irq_default_affinity(void)
56 * Linux has a controller-independent interrupt architecture.
57 * Every controller has a 'controller-template', that is used
58 * by the main code to do the right thing. Each driver-visible
59 * interrupt source is transparently wired to the appropriate
60 * controller. Thus drivers need not be aware of the
61 * interrupt-controller.
63 * The code is designed to be easily extended with new/different
64 * interrupt controllers, without having to do assembly magic or
65 * having to touch the generic code.
67 * Controller mappings for all interrupt sources:
69 int nr_irqs
= NR_IRQS
;
70 EXPORT_SYMBOL_GPL(nr_irqs
);
72 #ifdef CONFIG_SPARSE_IRQ
74 static struct irq_desc irq_desc_init
= {
76 .status
= IRQ_DISABLED
,
78 .handle_irq
= handle_bad_irq
,
80 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc_init
.lock
),
83 void init_kstat_irqs(struct irq_desc
*desc
, int cpu
, int nr
)
89 /* Compute how many bytes we need per irq and allocate them */
90 bytes
= nr
* sizeof(unsigned int);
92 node
= cpu_to_node(cpu
);
93 ptr
= kzalloc_node(bytes
, GFP_ATOMIC
, node
);
94 printk(KERN_DEBUG
" alloc kstat_irqs on cpu %d node %d\n", cpu
, node
);
97 desc
->kstat_irqs
= (unsigned int *)ptr
;
100 static void init_one_irq_desc(int irq
, struct irq_desc
*desc
, int cpu
)
102 memcpy(desc
, &irq_desc_init
, sizeof(struct irq_desc
));
104 spin_lock_init(&desc
->lock
);
109 lockdep_set_class(&desc
->lock
, &irq_desc_lock_class
);
110 init_kstat_irqs(desc
, cpu
, nr_cpu_ids
);
111 if (!desc
->kstat_irqs
) {
112 printk(KERN_ERR
"can not alloc kstat_irqs\n");
115 if (!init_alloc_desc_masks(desc
, cpu
, false)) {
116 printk(KERN_ERR
"can not alloc irq_desc cpumasks\n");
119 arch_init_chip_data(desc
, cpu
);
123 * Protect the sparse_irqs:
125 DEFINE_SPINLOCK(sparse_irq_lock
);
127 struct irq_desc
**irq_desc_ptrs __read_mostly
;
129 static struct irq_desc irq_desc_legacy
[NR_IRQS_LEGACY
] __cacheline_aligned_in_smp
= {
130 [0 ... NR_IRQS_LEGACY
-1] = {
132 .status
= IRQ_DISABLED
,
133 .chip
= &no_irq_chip
,
134 .handle_irq
= handle_bad_irq
,
136 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc_init
.lock
),
140 static unsigned int *kstat_irqs_legacy
;
142 int __init
early_irq_init(void)
144 struct irq_desc
*desc
;
148 init_irq_default_affinity();
150 /* initialize nr_irqs based on nr_cpu_ids */
151 arch_probe_nr_irqs();
152 printk(KERN_INFO
"NR_IRQS:%d nr_irqs:%d\n", NR_IRQS
, nr_irqs
);
154 desc
= irq_desc_legacy
;
155 legacy_count
= ARRAY_SIZE(irq_desc_legacy
);
157 /* allocate irq_desc_ptrs array based on nr_irqs */
158 irq_desc_ptrs
= alloc_bootmem(nr_irqs
* sizeof(void *));
160 /* allocate based on nr_cpu_ids */
161 /* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */
162 kstat_irqs_legacy
= alloc_bootmem(NR_IRQS_LEGACY
* nr_cpu_ids
*
165 for (i
= 0; i
< legacy_count
; i
++) {
167 desc
[i
].kstat_irqs
= kstat_irqs_legacy
+ i
* nr_cpu_ids
;
168 lockdep_set_class(&desc
[i
].lock
, &irq_desc_lock_class
);
169 init_alloc_desc_masks(&desc
[i
], 0, true);
170 irq_desc_ptrs
[i
] = desc
+ i
;
173 for (i
= legacy_count
; i
< nr_irqs
; i
++)
174 irq_desc_ptrs
[i
] = NULL
;
176 return arch_early_irq_init();
179 struct irq_desc
*irq_to_desc(unsigned int irq
)
181 if (irq_desc_ptrs
&& irq
< nr_irqs
)
182 return irq_desc_ptrs
[irq
];
187 struct irq_desc
*irq_to_desc_alloc_cpu(unsigned int irq
, int cpu
)
189 struct irq_desc
*desc
;
193 if (irq
>= nr_irqs
) {
194 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
199 desc
= irq_desc_ptrs
[irq
];
203 spin_lock_irqsave(&sparse_irq_lock
, flags
);
205 /* We have to check it to avoid races with another CPU */
206 desc
= irq_desc_ptrs
[irq
];
210 node
= cpu_to_node(cpu
);
211 desc
= kzalloc_node(sizeof(*desc
), GFP_ATOMIC
, node
);
212 printk(KERN_DEBUG
" alloc irq_desc for %d on cpu %d node %d\n",
215 printk(KERN_ERR
"can not alloc irq_desc\n");
218 init_one_irq_desc(irq
, desc
, cpu
);
220 irq_desc_ptrs
[irq
] = desc
;
223 spin_unlock_irqrestore(&sparse_irq_lock
, flags
);
228 #else /* !CONFIG_SPARSE_IRQ */
230 struct irq_desc irq_desc
[NR_IRQS
] __cacheline_aligned_in_smp
= {
231 [0 ... NR_IRQS
-1] = {
232 .status
= IRQ_DISABLED
,
233 .chip
= &no_irq_chip
,
234 .handle_irq
= handle_bad_irq
,
236 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc
->lock
),
240 int __init
early_irq_init(void)
242 struct irq_desc
*desc
;
246 init_irq_default_affinity();
248 printk(KERN_INFO
"NR_IRQS:%d\n", NR_IRQS
);
251 count
= ARRAY_SIZE(irq_desc
);
253 for (i
= 0; i
< count
; i
++) {
255 init_alloc_desc_masks(&desc
[i
], 0, true);
257 return arch_early_irq_init();
260 struct irq_desc
*irq_to_desc(unsigned int irq
)
262 return (irq
< NR_IRQS
) ? irq_desc
+ irq
: NULL
;
265 struct irq_desc
*irq_to_desc_alloc_cpu(unsigned int irq
, int cpu
)
267 return irq_to_desc(irq
);
269 #endif /* !CONFIG_SPARSE_IRQ */
272 * What should we do if we get a hw irq event on an illegal vector?
273 * Each architecture has to answer this themself.
275 static void ack_bad(unsigned int irq
)
277 struct irq_desc
*desc
= irq_to_desc(irq
);
279 print_irq_desc(irq
, desc
);
286 static void noop(unsigned int irq
)
290 static unsigned int noop_ret(unsigned int irq
)
296 * Generic no controller implementation
298 struct irq_chip no_irq_chip
= {
309 * Generic dummy implementation which can be used for
310 * real dumb interrupt sources
312 struct irq_chip dummy_irq_chip
= {
325 * Special, empty irq handler:
327 irqreturn_t
no_action(int cpl
, void *dev_id
)
333 * handle_IRQ_event - irq action chain handler
334 * @irq: the interrupt number
335 * @action: the interrupt action chain for this irq
337 * Handles the action chain of an irq event
339 irqreturn_t
handle_IRQ_event(unsigned int irq
, struct irqaction
*action
)
341 irqreturn_t ret
, retval
= IRQ_NONE
;
342 unsigned int status
= 0;
344 if (!(action
->flags
& IRQF_DISABLED
))
345 local_irq_enable_in_hardirq();
348 ret
= action
->handler(irq
, action
->dev_id
);
349 if (ret
== IRQ_HANDLED
)
350 status
|= action
->flags
;
352 action
= action
->next
;
355 if (status
& IRQF_SAMPLE_RANDOM
)
356 add_interrupt_randomness(irq
);
362 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
364 * __do_IRQ - original all in one highlevel IRQ handler
365 * @irq: the interrupt number
367 * __do_IRQ handles all normal device IRQ's (the special
368 * SMP cross-CPU interrupts have their own specific
371 * This is the original x86 implementation which is used for every
374 unsigned int __do_IRQ(unsigned int irq
)
376 struct irq_desc
*desc
= irq_to_desc(irq
);
377 struct irqaction
*action
;
380 kstat_incr_irqs_this_cpu(irq
, desc
);
382 if (CHECK_IRQ_PER_CPU(desc
->status
)) {
383 irqreturn_t action_ret
;
386 * No locking required for CPU-local interrupts:
388 if (desc
->chip
->ack
) {
389 desc
->chip
->ack(irq
);
391 desc
= irq_remap_to_desc(irq
, desc
);
393 if (likely(!(desc
->status
& IRQ_DISABLED
))) {
394 action_ret
= handle_IRQ_event(irq
, desc
->action
);
396 note_interrupt(irq
, desc
, action_ret
);
398 desc
->chip
->end(irq
);
402 spin_lock(&desc
->lock
);
403 if (desc
->chip
->ack
) {
404 desc
->chip
->ack(irq
);
405 desc
= irq_remap_to_desc(irq
, desc
);
408 * REPLAY is when Linux resends an IRQ that was dropped earlier
409 * WAITING is used by probe to mark irqs that are being tested
411 status
= desc
->status
& ~(IRQ_REPLAY
| IRQ_WAITING
);
412 status
|= IRQ_PENDING
; /* we _want_ to handle it */
415 * If the IRQ is disabled for whatever reason, we cannot
416 * use the action we have.
419 if (likely(!(status
& (IRQ_DISABLED
| IRQ_INPROGRESS
)))) {
420 action
= desc
->action
;
421 status
&= ~IRQ_PENDING
; /* we commit to handling */
422 status
|= IRQ_INPROGRESS
; /* we are handling it */
424 desc
->status
= status
;
427 * If there is no IRQ handler or it was disabled, exit early.
428 * Since we set PENDING, if another processor is handling
429 * a different instance of this same irq, the other processor
430 * will take care of it.
432 if (unlikely(!action
))
436 * Edge triggered interrupts need to remember
438 * This applies to any hw interrupts that allow a second
439 * instance of the same irq to arrive while we are in do_IRQ
440 * or in the handler. But the code here only handles the _second_
441 * instance of the irq, not the third or fourth. So it is mostly
442 * useful for irq hardware that does not mask cleanly in an
446 irqreturn_t action_ret
;
448 spin_unlock(&desc
->lock
);
450 action_ret
= handle_IRQ_event(irq
, action
);
452 note_interrupt(irq
, desc
, action_ret
);
454 spin_lock(&desc
->lock
);
455 if (likely(!(desc
->status
& IRQ_PENDING
)))
457 desc
->status
&= ~IRQ_PENDING
;
459 desc
->status
&= ~IRQ_INPROGRESS
;
463 * The ->end() handler has to deal with interrupts which got
464 * disabled while the handler was running.
466 desc
->chip
->end(irq
);
467 spin_unlock(&desc
->lock
);
473 void early_init_irq_lock_class(void)
475 struct irq_desc
*desc
;
478 for_each_irq_desc(i
, desc
) {
479 lockdep_set_class(&desc
->lock
, &irq_desc_lock_class
);
483 #ifdef CONFIG_SPARSE_IRQ
484 unsigned int kstat_irqs_cpu(unsigned int irq
, int cpu
)
486 struct irq_desc
*desc
= irq_to_desc(irq
);
487 return desc
? desc
->kstat_irqs
[cpu
] : 0;
490 EXPORT_SYMBOL(kstat_irqs_cpu
);